Filled two-piece gelatin capsules for the encapsulation of various medicinal agents have been used for administering drugs since the mid-19th century. This capsule form of medicament proved to be very popular because hard gelatin capsules are tasteless, easily administered and easily filled either at a pharmacy or pre-filled in large quantities at commercial plants. While hard shell gelatin capsules are still popular dosage forms for pharmacist dispensed medicaments they have generally been discontinued in many over-the-counter products because of the risk of tampering with their contents.
Absent the susceptibility of capsule form medicaments to tamperings the capsule form was extremely popular with consumers because of a number of advantages. Many consumers prefer the gelatin form of capsule because of the perceived efficacy, taste, feel and swallowability of the gelatin capsule form of medicament.
This consumer preference for gelatin capsule-like medicaments provided a challenge to the industry to produce capsule-like medicaments which are tamper-proof yet provide the consumer with the advantages of a hard shell gelatin capsule-like dosage form. Norbert I. Berta developed simulated capsule-like medicaments and a process for making such capsule-like medicaments as disclosed in his U.S. Pat. No. 4,820,524. The entire disclosure of this issued U.S. patent is hereby incorporated herein by reference. Norbert I. Berta has also developed variations of the processes for making simulated capsule-like medicaments and apparatus for producing such medicaments as disclosed in co-pending U.S. patent application Ser. Nos. 129,108 filed Dec. 4, 1987; 129,109 filed Dec. 4, 1987; 190,551 filed May 5, 1988; and 190,616 filed May 5, 1988. The simulated capsule-like medicaments developed by Berta were responsive to a long felt need in the industry to provide a simulated substitute for the popular dosage form of gelatin capsules. While gelatin coating of uncoated compressed medicaments such as acetaminophen is possible in accordance with the invention of Berta, it is difficult to control the quality of the surface appearance of such gelatin-coated caplets.
Beyond the development of a simulated capsule-like medicament several factors and considerations must be met to commercially produce a capsule which has a smooth, uniform and substantially bubble free outer coating appearance. A preferred gelatin-coated caplet is one in which two distinctly colored gelatin coating solutions are utilized to produce a bi-colored gelatin-coated caplet. The two overlapping distinctly colored gelatin coatings form a seam about the transverse axis of the medicament. The presence of this seam and the distinct bi-coloring contributes to the consumer's perception of these simulated capsule-like medicaments as equivalents to gelatin capsule dosage forms.
The gelatin coated caplet product must adequately simulate a capsule-like medicament from a consumer's sight and touch perspective and must therefore be absent of discoloration, pits and gouges. The presence of such physical imperfections may erode the consumer's perception as to the gelatin coated caplet's capsule-like nature and the tamper-free nature of this dosage form. Strong consumer confidence in the gelatin capsule-like nature and tamper-resistance of the simulated capsule medicament of the invention is of the utmost importance in the marketing of this dosage form and forms an object of the present invention. It is therefore an object of the present invention to provide a subcoating for a solid caplet medicament core which minimizes bubble formation, discoloration and other aesthetic imperfections to provide for a smooth, uniform and substantially bubble free outer coating appearance to simulated capsule-like medicaments.